Delisting procedure: Each spamrats RBL has their own delisting requirements, which can be found at the ‘Delisting link’ mentioned above, so, you will first need to see on which of their RBL your IPs are blacklisted on, then follow the delisting procedures associated with those RBLs.

Additional info: this RBL contains data from all spamrats RBLs, all into one blacklist.